See roll.
The left-to-right or horizontal movement of the engraving spindle.
The horizontal axis of a two-dimensional plot in Cartesian coordinates.
The horizontal axis in a chart. It displays the range of values possible for the independent variable to take. In time series data, the x-axis represents time.
By convention this is the horizontal axis on a graph.
Usually, the axis in the plane of the laminate used as 0° reference. Typically, the y-axis is the axis in the plane of the laminate perpendicular to the x-axis, and the z-axis is the reference axis normal to the laminate plane in the composite laminate. (See also laminate coordinate axes, off-axis laminate and principal axis.)
Referred to as X-Axis and X Axis; An imaginary line passing left-to-right through the center of the plan view. The left-right direction on the diagram sheet is when it is held in the position to read the text. This imaginary line is used for referance point in both 2D and 3D drawings/drafting.
[n] - the horizontal axis in a plane coordinate system
The horizontal axis on a graph. The line going across the page.
East West movement (left to right) is in x
The horizontal axis in the plane. See also: Axis, y axis.
The horizontal number line on a coordinate plane 
noun the horizontal axis in a plane coordinate system
(DOD) A horizontal axis in a system of rectangular coordinates; that line on which distances to the right or left (east or west) of the reference line are marked, especially on a map, chart, or graph.
The horizontal axis in a coordinate plane.